As people across the globe are experiencing hallucinations, MI5 agent Zoe contacts Bill for answers; Catherine Durand detects unusual black hole activity.

As Adina starts the next stage of her plan, astronauts Juliet and Richard see warning signs in space; uncovering Adina's sinister mission.

With Richard's help, Catherine discovers she can travel to another world; a new revelation puts Martha's loyalties to the test; Zoe breaks Bill out of prison.

Tom grapples with a betrayal and encounters a familiar face; Catherine looks for a solution to the dangers of the black hole.

A deadly face-off leads to a life-threatening moment; Catherine and Sam seek help for his parents.

Bill's latest discovery is put in jeopardy, even as trouble brews with the human aliens; Catherine must decide where her loyalties lie.

Adina's plan for world destruction reaching completion; those in the alternate world are under attack.

With Adina's plan in motion, the world's last hope is for Bill to make one more journey, risking his own life in search of Catherine's help.